Xref: utzoo comp.lang.c:18338 comp.lang.fortran:2005
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From: tim@crackle.amd.com (Tim Olson)
Newsgroups: comp.lang.c,comp.lang.fortran
Subject: Re: Calling FORTRAN from C (Was: Need matrix inversion C routine).
Message-ID: <25509@amdcad.AMD.COM>
Date: 3 May 89 23:42:50 GMT
References: <2846@tank.uchicago.edu> <5785@cbnews.ATT.COM> <10087@smoke.BRL.MIL> <1544@auspex.auspex.com> <1278@l.cc.purdue.edu>
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In article <1278@l.cc.purdue.edu> cik@l.cc.purdue.edu (Herman Rubin) writes:
| I have used several operating systems before UNIX.  On all of them, a name
| was a name was a name.  The program cards and subroutine cards in Fortran
| produced names in the object file identical to what appeared on the card.
| Entry names and COMMON block names likewise.  Assembler-produced programs
| did the same thing.  If I was going to use an Algol program it would still
| be the same.  The calling sequence was a problem, even between Fortrans.
| But not the names.

If an underscore is not prepended (or the names changed in some standard
unique way), then you run into the problem of potential name-space
conflicts with the assembly-level "helper" routines that almost always
exist.  These routines include "start" (the beginning of crt0, which
gets control and sets everything up for your program), help for non- or
undersupported intrinsics like unsigned modulo, short multiplies, etc.

If this were not done, then a user would just get mysterious
"multiply-defined" errors from the link of his program.


	-- Tim Olson
	Advanced Micro Devices
	(tim@amd.com)